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Sailboat Lightning Protection

Discussion in 'Musings With Maine Sail' started by Lubber No More!, Jul 11, 2018. Add this thread to a FAQ

  1. Lubber No More!

    Lubber No More!

    Joined Jul 11, 2018
    1 posts, 0 likes
    Catalina 42
    Endless Journey US Herrington Harbour Marina
    I've read about setting up a boat for lightning protection in a number of books. Does anyone have any practical experience? Does running a ground through the mast down to the water really make a difference? Or the fuzzy "diffuser" up at the top of the mast? Or is it just luck of the draw.

    Not worried so much about the electronics or things that can be replaced. Thinking more of protecting the integrity of the boat and the safety of those onboard.

    Thanks,
    Sal
     


  2. Roland5048

    Roland5048

    Joined May 12, 2004
    1,025 posts, 287 likes
    Hunter Cherubini 30
    US New Port Richey
    IMHO, yes.
     


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  3. dlochner

    dlochner

    Joined Jan 11, 2014
    2,108 posts, 747 likes
    Sabre 362
    113 US Fair Haven, NY


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  4. Ron20324

    Ron20324

    Joined Jan 22, 2008
    6,107 posts, 541 likes
    Beneteau 323
    US Annapolis MD
    Everytime this subject comes up, I repeat a news video on TV a few years ago. Someone inside a marina office was filming the storm belting the marina. He just happen to capture a lightning bolt as it ignored two sailboats but hit a smaller cabin cruiser in the slip in between them. Make your own conclusions, but mine is that lightning will go where it wants to go.
     


    Last edited: Jul 12, 2018
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  5. Gunni

    Gunni

    Joined Mar 16, 2010
    5,079 posts, 961 likes
    Beneteau 411 Oceanis
    US Annapolis
    The Beneteaus are built with a stranded cable that connect the chainplate to a keel bolt. I sailed with a guy who carried a 10ft section of anchor chain which he shackled to a shroud turnbuckle and dropped over the side. I adapted that chain concept to a sailing kayak I used during expedition races. While I have not been struck by lightening I have had bolts strike to both the port and starboard in quick succession. Once had my hair stand on end while answering natures call off the stern, sensing my potential "connection of the circuit" I fell to the deck as a lightening bolt struck the water behind the boat. That was exciting! I chalk my good fortune up to clean-living and a non-imminent need for me in the great beyond!
     


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  6. Don S/V ILLusion

    Don S/V ILLusion

    Joined Sep 25, 2008
    5,031 posts, 265 likes
    Alden 50
    US Sarasota, Florida
    Congrats to those who spelled lightning correctly.

    Lee Trevino was struck by lightning and he claimed his putting improved so look at the bright side.
     


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  7. Sailm8

    Sailm8

    Joined Feb 21, 2008
    1,490 posts, 164 likes
    Hunter 29.5
    US Punta Gorda
    PO installed one of those bottle brush talisman on my mast. I got hit anyway..
     


  8. All U Get

    All U Get

    Joined Oct 2, 2008
    2,539 posts, 269 likes
    Pearson/ 530
    US Strafford, NH
    Oops, way to go Ron.
     


  9. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,608 posts, 1,090 likes
    O'Day 19
    US Littleton, NH
    Electrons are known to repel eachother. I would think, with that much potential, anything inside an aluminum mast would be the last path electricity would choose to travel. The outside of the mast seems little a better choice. Even the standing rigging would collect electrons adhering to conductive surfaces while they repel eachother to farther conductive surfaces. Whatever the overall least resistance to ground.

    - Will (Dragonfly)
     


  10. jssailem

    jssailem

    Joined Oct 22, 2014
    5,595 posts, 1,892 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    Are you a
    • “Lightning leaps from the clouds and smites your boat on the water.”
    Or
    • “My boat is so generous it raises up the Lightning bolts and gives it to the gods”
    Thinker.
     


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  11. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,608 posts, 1,090 likes
    O'Day 19
    US Littleton, NH
    I prefer the latter way of thinking and now that I have been introduced to that way of thinking, that's how I will always think of it.

    - Will (Dragonfly)
     


  12. Stan Breaux

    Stan Breaux

    Joined Feb 8, 2007
    134 posts, 6 likes
    Catalina 36 MKII
    US Pensacola Beach, FL
    My Catalina 36 was struck by lightning near Pensacola in late 2016 while my wife and son and I plus dog were aboard and in the main cabin. My boat has no special lightning protection. The mast is keel-stepped.
    It was the loudest boom we had ever heard, and various things exploded -- most notably the bilge pump which blasted the access board covering it out of the floor, throwing our dog (who was lying on it) into the air. Various switches exploded. Almost everything electric was ruined. Minor electrical fire in the alternator.
    We called TowBoatUS and got a tow to the marina that would do the repairs.
    Funny thing is, I was standing only about 2 feet from the mast, and I didn't even feel a tingle. Neither did my wife or son who were also in the main cabin. We felt as if we had been in an explosion, but didn't feel an electrical shock.
    So it seems like you MIGHT be very safe (at least from electrocution) even if your boat is struck while you are on it.
    I have to say, though, we were in a huge lightning storm again last week, and it will really make you think. I was nervous the whole time thinking it would happen again.
     


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  13. jssailem

    jssailem

    Joined Oct 22, 2014
    5,595 posts, 1,892 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    Uncle NOAA says.
    Does lightning strike from the sky down, or the ground up?
    The answer is both. Cloud-to-ground lightning comes from the sky down, but the part you see comes from the ground up. A typical cloud-to-ground flash lowers a path of negative electricity (that we cannot see) towards the ground in a series of spurts. Objects on the ground generally have a positive charge. Since opposites attract, an upward streamer is sent out from the object about to be struck. When these two paths meet, a return stroke zips back up to the sky. It is the return stroke that produces the visible flash, but it all happens so fast - in about one-millionth of a second - so the human eye doesn't see the actual formation of the stroke.
     


  14. jssailem

    jssailem

    Joined Oct 22, 2014
    5,595 posts, 1,892 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    So if we painted our bottoms with rubber would we be protected from lightning in our boats.
     


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  15. Gunni

    Gunni

    Joined Mar 16, 2010
    5,079 posts, 961 likes
    Beneteau 411 Oceanis
    US Annapolis
    I watched lightning glance off the mast of one boat's mast in the St.Augustine anchorage and ground through an adjacent boat. The second boat was the one that took the damage. All the electrics appeared to be fried.
     


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  16. jssailem

    jssailem

    Joined Oct 22, 2014
    5,595 posts, 1,892 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    Never seen lightning strike on a boat.

    I did get to see Saint Elmo’s Fire once on an airplane.
     


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  17. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,608 posts, 1,090 likes
    O'Day 19
    US Littleton, NH
    Consider all that insulating air the lightning just arched across. Does a few mm of rubber seem like that much?

    - Will (Dragonfly)
     


  18. Meriachee

    Meriachee

    Joined Aug 1, 2011
    2,535 posts, 674 likes
    Catalina 270
    CA Wabamun - on the orange ball
    Does this imply that if we painted the whole boat in rubber, we would be protected and dry at the same time, while offering impact protection from the dreaded fishing boats? Not to mention the stealth argument.
     


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  19. Don S/V ILLusion

    Don S/V ILLusion

    Joined Sep 25, 2008
    5,031 posts, 265 likes
    Alden 50
    US Sarasota, Florida
    My theory is that Ben Franklin was right - copper in typical bottom paint attracts lightning and grounding expedites the process. And umbrellas attract wind and trailer parks attract hurricanes.
     


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  20. Meriachee

    Meriachee

    Joined Aug 1, 2011
    2,535 posts, 674 likes
    Catalina 270
    CA Wabamun - on the orange ball
    Don, so you're saying that if you put the keel in the dirt on a regular basis, you are more likely to get hit by lightning?
     



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